Method of dehydrating pine oil



Patented June 4,

" l 1 METHOD JOFDEHYDBATING PINE 011. A

sereilec. Norton, BrunswickfGa assignor m Hercules Powder 'Company, ,Wilmington, DeL,

,1 'a'corporation of Delaware it a bidDrawi ngi Applicationalurieilll,1931,

a. 1Serial;No;545,499-.

sjclaims. (01. 2 0 167) This invention relates to method for effecting the dehydration ofi-pine oiLthallyiS togsay, more particularly for eifecting thedehydrationgof tertiary alcohols contained in pine oil. ,1. PineO LMasis well known, is produced i'rom pine wood and more particularly-"from southern yellow pine wood, by distillation. 1 Pine oil; as 1 well known, comprises various components 'iIl-g eluding hydrocarbons, oxygenated bodies, suchgas borneol, anetholgmethyl chavicol, ,etc;., secondary alcohols, as fenchyl alcohol, etc., but iscom posed largely of tertiary alcohols of Which ter Pumas" as oltare. n ominating proportion. r

with, for example, turpentine.

, Pine oil as such has, been recognizedias }of limited use in the commercial arts due to the.

large content of tertiary alcohols as compared Furt rliwh b the oxygenated bodies contained in .pine oil are N of value, theirrecovery or separation frompine oi1=is ,difiicult because of their solubility in the tertiary alcohols. On theother'hand, 'itfhas been recognized that if the tertiary alcoholsTbe ee hydrated, that is, converted into hydrocarbons andwater, a product comparable for use in the commercial arts with turpentine and usable as j a substitute therefor may be obtained, or where' recovery or separation 0f,\for-example, the oxyge'n'ated bodies is desired, such maybe readily eiiected after dehydration of the pine oil.

Heretofore, various :methods have been. suggested for effectinglthe' dehydrationof ipine .oil in connection, for example, with the production of turpentine substitute, the recovery or separa- I tion of oxygenated bodies, etc, Among the methods heretofore suggested, it has been proposed to efiect the dehydrationof pine oil byheating in the presence of, for example, fullers earth, other argillaceous earths, activated carbon and iodin, as disclosed, for example, in the Patent No. 1,772,895, dated August 12, 1930, to Irvin W. Humphrey, and by the use of hydriodic acid, as

disclosed in the Patent No. 1,772,546, dated' August 12, 1930; to Irvin W. Humphrey, etc.

The methods heretofore suggested for, effecting the dehydrationof pine oil are open to'various disadvantages in, for example, that in order to effect the dehydration at temperatures at which excessive polymerization of the hydrocarbons may be avoided the dehydration is by no means complete. 'Thus, for example, where the dehydration is efiected by heating in the'presenceof fullers earth only about 60% of the tertiary alcohols are dehydrated using atemperature of 150 C. and a comparatively large amount of polymerization :takes place, about 15% of polymerized hydrocarbons being produced.

. Now, .it'jis the objectof thisinvention to provide amethod for the dehydration of pine oil, that is foreifecting the conversion of tertiary al-' 5 cohols contained in pine oil into hydrocarbons the procedure maybe carried out at a lower temperature ithan'heretofore, with increase in the percentage of tertiary alcohols dehydrated and decrease in the amount of polymerized products produced.

In accordancewith the method embodying this invention,; pine oil is subjected to heating in the presence of silica gel Desirably, the treatment is effected in the presence of,,in addition to silica gel, :an organic dibasic acid or anhydride, as for 1 example, phthalic anhydride, ,phthalic acid, tarused without any treatment.

' As-has :been'indicated, the organic dibaslc acid or .anhyd'ride may i be, phthalic anhydride,

phthalic acid itartaric .:acid, oxalic-acid, etc.,=;it being understood thatieither the acid or the anhydride may be used equivalently. The acid or anhydride may be used in any desired amount, but foreconomy and due to the fact that itwill react with secondary alcohols present in the pine oil and cannot be recovered except by chemical means, it will desirably be used in relatively small amount, say 0.1% to 1% of the pine oil.

In carrying out the treatment, the pine oil will 'be heated in the presence of silica gel, .or of silica. gel and organic dibasic acid, at any suitable temperature at which the desired dehydration will be efiected and below that at which undesirable polymerization will take place. The treatment may be carried out, for example, at a temperature within say about the range about- C. to about 0., or within the; broader range about 90 C. to about C. i

As illustrative of the carrying out of the'method embodying this invention, for example, to a quantity of pine oil there is added about 1% of 55 addition tothe silica gel, completefdehydration of the tertiary alcohols will be obtained with the formation of only about 13% polyme'rized'prodnets, and even with the use of a temperature somewhat below C. After dehydration'is "effected the hydrocarbons formed" may be 'distilled off, say using, for example, atemperature of C. under a pressure of 100mm. mercury, or, if desired, the procedure for effecting dehydration may be carried out under reduced pressure, say 10 mm. mercury, at, whichlthe'hydrocarbons will distill off at the temperature of 100 C. used.

As a further illustration, for example, to a quantity of pineoilthere'is added 11% silica, gel and 0.1%phthalic anhydride. The pine oil is then heated to 100 C. under'reduced pressure, say a pressure of 1 about 10 mm; mercury, to per-' mit distillation ofi of the hydrocarbons as formed. l

In carrying out the method in accordance with this invention, the distillate will be found to comprise largely dipenteneand to have-valuable properties as a turpentine substitute, solvent and for other uses in the oomrnercialarts. The residue will be found to comprise largely a mixtureof secondary alcohols, oxygenatedbodies, ketones; ethe rs asmall amountof polymerized products and the corresponding ester of borneol or of fenchyl alcohol equivalent-to the acid" or anhydride added. The residue will be found to be adapted for "various'uses, such, for.

example, as a disinfectant, oritmay be treated for separation of its constituents, such as secondary alcohols, oxygenated bodies, etc.

It will now be noted that the method-in acsity for any treatmentfor efiecting its regenera tion, thus effecting a saving. 'The'acid'or anhy-' ary'alcohol present in the pine oil for the ior-.

mation" of the corresponding ester.

- dibasic acid.

3. Themethod of dehydrating pine oil which includes heating pine oil to a temperature within the range about 90 C. to about C. in the presence of silica gel andan organic dibasic acid.

4. The method of dehydrating pine oil which includes heating pine oil in the presence of silica gel and an organic dibasic acid to a temperature and under a pressure such that hydrocarbons will be distilled off as formed.

5. The method of dehydrating pine oil which includes heating pine oil in the presence of silica gel and phthalic anhydride at a temperature not substantially in' excess of C. p

6. The method of dehydrating pine oil which includes heating pine oil in the presence of silica gel and tartaric acid.

'7. The method of dehydrating pine oil which includes heating pine oil in the presence of silica gel and oxalic acid. a r

8. The method of dehydrating pine oil which includes heating pine oil in 'the'presence of silica gel and an organic dibas'ic acid at a temperature within the range about 100 C. to about 150 C.

9. The method of dehydrating pine oil which includes heating pine'oil in the presence of silica gel and phthalic anhydride. Y '10. The method of dehydrating pine oil whic h includes heating pine oil in the presence of silica geland tartaric acid at a temperature not substantiallyin excess of 150 C.

11. The method of dehydrating pine oil which includes heating pine'oil in the presence of silica gel and oxalic acid at a temperature not substantially in excess of 150 C. I [12. The method of dehydrating pine oil which includes heating pine oil in the presence of 0.1 %-2% of silica gel and an organic dibasic acid. 13. The method ofdehydrating pine oil which includes heating pine oil in the presence of- 0.1%-2% of silica gel and 0.1%'-1.0% of an organic dibasic acid. SERENO G. NORTON; 

